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//---------------------------------------------------------------------
// <copyright file="ReferentialConstraint.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Data.Common;
namespace System.Data.Metadata.Edm
{
/// <summary>
/// This class describes referential constraint on the relationships
/// </summary>
public sealed class ReferentialConstraint : MetadataItem
{
#region Constructors
/// <summary>
/// Constructs a new constraint on the relationship
/// </summary>
/// <param name="fromRole">role from which the relationship originates</param>
/// <param name="toRole">role to which the relationship is linked/targeted to</param>
/// <param name="toProperties">properties on entity type of from role which take part in the constraint</param>
/// <param name="fromProperties">properties on entity type of to role which take part in the constraint</param>
/// <exception cref="ArgumentNullException">Argument Null exception if any of the arguments is null</exception>
internal ReferentialConstraint(RelationshipEndMember fromRole,
RelationshipEndMember toRole,
IEnumerable<EdmProperty> fromProperties,
IEnumerable<EdmProperty> toProperties)
{
_fromRole = EntityUtil.GenericCheckArgumentNull(fromRole, "fromRole");
_toRole = EntityUtil.GenericCheckArgumentNull(toRole, "toRole");
_fromProperties = new ReadOnlyMetadataCollection<EdmProperty>(new MetadataCollection<EdmProperty>(
EntityUtil.GenericCheckArgumentNull(fromProperties, "fromProperties")));
_toProperties = new ReadOnlyMetadataCollection<EdmProperty>(new MetadataCollection<EdmProperty>(
EntityUtil.GenericCheckArgumentNull(toProperties, "toProperties")));
}
#endregion
#region Fields
private RelationshipEndMember _fromRole;
private RelationshipEndMember _toRole;
private readonly ReadOnlyMetadataCollection<EdmProperty> _fromProperties;
private readonly ReadOnlyMetadataCollection<EdmProperty> _toProperties;
#endregion
#region Properties
/// <summary>
/// Returns the kind of the type
/// </summary>
public override BuiltInTypeKind BuiltInTypeKind { get { return BuiltInTypeKind.ReferentialConstraint; } }
/// <summary>
/// Returns the identity for this constraint
/// </summary>
internal override string Identity
{
get
{
return this.FromRole.Name + "_" + this.ToRole.Name;
}
}
/// <summary>
/// Returns the FromRole which takes part in this referential constraint
/// </summary>
/// <exception cref="System.ArgumentNullException">Thrown if value passed into setter is null</exception>
/// <exception cref="System.InvalidOperationException">Thrown if the ReferentialConstraint instance is in ReadOnly state</exception>
[MetadataProperty(BuiltInTypeKind.RelationshipEndMember, false)]
public RelationshipEndMember FromRole
{
get
{
return _fromRole;
}
}
/// <summary>
/// Returns the ToRole which takes part in this referential constraint
/// </summary>
/// <exception cref="System.ArgumentNullException">Thrown if value passed into setter is null</exception>
/// <exception cref="System.InvalidOperationException">Thrown if the ReferentialConstraint instance is in ReadOnly state</exception>
[MetadataProperty(BuiltInTypeKind.RelationshipEndMember, false)]
public RelationshipEndMember ToRole
{
get
{
return _toRole;
}
}
/// <summary>
/// Returns the collection of properties on the from role on which the constraint is defined on
/// </summary>
[MetadataProperty(BuiltInTypeKind.EdmProperty, true)]
public ReadOnlyMetadataCollection<EdmProperty> FromProperties
{
get
{
return _fromProperties;
}
}
/// <summary>
/// Returns the collection of properties on the ToRole on whose value the constraint is defined on
/// </summary>
[MetadataProperty(BuiltInTypeKind.EdmProperty, true)]
public ReadOnlyMetadataCollection<EdmProperty> ToProperties
{
get
{
return _toProperties;
}
}
#endregion
#region Methods
/// <summary>
/// Overriding System.Object.ToString to provide better String representation
/// for this type.
/// </summary>
public override string ToString()
{
return this.FromRole.Name + "_" + this.ToRole.Name;
}
/// <summary>
/// Sets this item to be read-only, once this is set, the item will never be writable again.
/// </summary>
internal override void SetReadOnly()
{
if (!IsReadOnly)
{
base.SetReadOnly();
RelationshipEndMember fromRole = FromRole;
if (fromRole != null)
{
fromRole.SetReadOnly();
}
RelationshipEndMember toRole = ToRole;
if (toRole != null)
{
toRole.SetReadOnly();
}
this.FromProperties.Source.SetReadOnly();
this.ToProperties.Source.SetReadOnly();
}
}
#endregion
}
}
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